Harness assembly and method of making same



April 30, 1963 W. A. PLUMMER HARNESS ASSEMBLY AND METHOD OF MAKING SAME Filed Nov. 2, 1959 IN V EN TOR. 094 75? /7. PL (/MMEQ BY I 47 OQ/VEU United States Eatent f 3,687,983 Patented Apr. 30, 1963 3,937,983 HARNESS ASEMBLY AND METHQD F MAKING SAME Walter A. Plummet, 3546 Crownridge Drive, Sherman Gaks, Calif. Filed Nov. 2, i959, Ser. No. 85%496) 5 tClairns. (Ci. l74-6t) This invention relates to harness assemblies and more particularly to an improved assembly of this character and to a method of fabricating the same featuring in particular a mode of increasing the circuit-forming capabilities thereof and to a technique for prolonging the service life of existing but inadequate harness assemblies.

Not infrequently it is found that an existing wire harness assembly is inadequate or unsuitable for continued use either because certain of its conductors are defective or unserviceable or because the existing harness assembly lacks desired circuit capabilities required for expanding requirements in a particular installation. As is well known, such harness assemblies are employed to interconnect instrumentation at separated locations either within a single enclosure or in spaced enclosures or remotely from other equipment. Such assemblies include a main trunk line of conductors and a surrounding protective sheath, the terminal ends of the individual conductors being fanned out and connected to cable heads, terminal strips or the like for convenience in making connections to instrumentation. Particular conductors may become shorted, broken or otherwise unsuitable for continued use. Likewise, there may be a need for the use of additional accessories of instrumentation requiring additional circuits in the harness assembly. Heretofore, it has been necessary to survey the inadequate harness assembly and to replace it with a complete new assembly meeting the new requirements of the operating environment. Such survey of inadequate harness assemblies can be very costly in materials as well as in the time required for the substitution of the new assembly. Owing to time limitations or the high costs involved in replacing the harness, it has sometimes been necessary to resort to dangerous practices such as the addition of the required number of wires by stringing them loosely along the trunk of the installed cable assembly. While the risk involved in this practice may be taken in emergencies, it cannot be countenanced as acceptable for obvious reasons.

By the present invention there is provided a highly satisfactory and inexpensive solution for the above mentioned and related problems encountered in the use of harness assemblies. By adoption of the technique of the invention, it is no longer necessary to survey the inadequate harness assembly, nor is it necessary to provide a supplemental or parallel assembly. Instead the number of insulated conductors required to establish the requisite circuits in cooperation with the existing satisfactory conductors are laid along the length of the existing assembly. In cases where the existing main trunk is freely accessible on all sides it is generally preferable to spiral the new conductors about the protective sheathing of the existing cable to assure that these conductors will be evenly distributed and held compactly against the former assembly. Where this is not feasible, the new conductors may be laid beside the old and suitably tied in place in the man ner found most convenient. For example, pressure sensitive tape may be used at intervals to secure the new conductors to the old or a single tie of any suitable material may be spirally wrapped about the conductors and the main trunk of the old system. Thereafter, a tubular jacket of flexible waterproof material having a longitudinal seam is assembled about both the cable and the newly added conductors for the full length of the assembly and securely closed thereby providing a protective sheath enclosure for both the old and the new conductors and providing substantially the same amount of protection for the old assembly as was previously afforded the original conductor.

Desirably, the new jacket is formed of heat reactive plastic material for ease and convenience of assembly while loose and thereafter shrunk snugly about the wiring by subjecting the jacket to heat thereby providing a very smooth compact and neat-appearing harness assembly fully as serviceable, eflicient and effective as though the entire assembly included but a single sheath.

Accordingly, it is a primary object of the present invention to provide novel means, technique and method for salvaging inadequate cable harness assemblies and extending the service life of existing or installed assemblies.

Another object of the invention is the provision of a technique by which the circuit handling capabilities of existing cable harness assemblies can be expanded to any desired extent simply, inexpensively and in a minimum of time without sacrificing existing functional circuits or disturbing them in any way and while providing a cable harness assembly of expanded capabilities which is as fully efiicient and as adequately protective as was the original installation.

These and other more specific objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawing to which they relate.

Referring now to the drawing in which a preferred embodiment of the invention is illustrated.

FIGURE 1 is a general view of a typical wire harness operating environment making use of the present invention;

FIGURE "2 is an enlarged perspective view illustrating the technique of expanding the circuit capabilities of an existing but inadequate cable harness assembly employing the principles of the present invention; and

FIGURE 3 is a cross-sectional view of the completed assembly taken along line 3-3 on FIGURE 2.

Referring to the drawings, there is shown in FIGURE 1 an illustrative operative environment having use for a fluid-tight harness assembly to interconnect firing instrurnentation carried by a mobile firing station '10 and other instrumentation located at missile launching device 11. The harness assembly 12 interconnecting mobile station It) and launching apparatus '11 comprises a plurality of insulated conductors 1'4 enclosed within a heavy duty protective sheath 15. The terminal ends of harness assembly 12 are not shown since these terminal facilities differ widely, fall outside the scope of this invention, and are well known to those skilled in this art. In operating environments such as that illustrated in FIGURE 1, it is customary for each end of the harness assembly to be formed by plug-in type cable head assemblies. In other instances the individual conductors terminate at separate 3 terminal posts secured to terminal strips of insulating material.

Assuming that it is desired to use the facilities of operating station to operate a launcher 11 having need for a larger number of circuits than can be accommodated by the conductors of an existing harness assembly or that one or more of the existing conductors 14 is not serviceable, workmen lay out the required number of additional conductors 16 along the existing assembly. The new conductors preferably are wrapped spirally about the trunk of the old harness while distributed in side-by-side relation about the exterior of sheathing \15. Where spiral-ling of the new conductors about the old assembly is not feasible as is the case, for example, when the existing wire harness is mounted within a cabinet or along partition walls, separate ties may be employed to secure the new conductors compactly in place. Depending upon the accessibility and length of the assembly, the ties can be wrapped spirally about conductors 16 or individual ties can be made at intervals along the assembly. It will be recognized that ties for the conductors are not essential but do aid in preventing displacement and bunching of the conductors and serve as a convenience in holding the wires in place and against crossing one another during assembly of jacket-ing 18.

Iacketing 18 forming an important feature of the invention may consist of any suitable flexible material having provision for joining its lateral edges to hold the jacket snugly assembled about the trunk portion of the expanded harness unit. Preferably and desirably, jacket 18 is formed of fluid-tight thin sheet plastic material having interfitting tongues and grooves 19, 20* along its opposite lateral edges cooperating with one another to form a fluid-tight interlocking seam 21. It is desirable to employ commonly known commercially available heat reactive plastic material for the main body of the jacket having the characteristic of shrinking approximately to percent when heated to an appropriate temperature. In fact, jacketing 18 may be of the type disclosed in the co-pending application for United States Letters Patent Serial No. 85 0,127, filed concurrently herewith by Walter A. Plummer and Richard A. Sperr, one commercial source of such material being Minnesota Mining and Mfg. Co., which company identifies the material as Irvington Brand #3024, heat reactive plastic. To facilitate closure of the jacket, seam 21 is provided with a suitable hand operated slide device 22 having a pivoting pull tab .23 to facilitate movement of the device along the seam. A suitable liquid sealant may be and preferably is applied along one or both of the interfitting tongues and grooves 19 and 26 to seal the same permanently closed against the passage otE fluid after they are interlocked together by use of slide device 22.

It will be understood that the full length of the existing harness assembly and of newly added conductors 16 except the very terminal ends of each are enclosed preferably by a continuous length of jacketing 18 to insure against the possibility of fluid or foreign material entering the jacket. After seam 21 has been closed, jacketing 18 may be uniformly heated to the requisite temperature and for the period required to heat-shrink the heat reactive jacket snugly about the enclosed wires and cabling. In cases where non-reactive material is employed, the heat-shrinking treatment step will be unnecessary. Desirably, the heat treatment takes place progressively along the length of the jacket in order that the lengthwise shrinkage of the jacket may occur without imposing internal tension strains on the jacket. After the jacket has been heat-shrunk to the underlying components, the ends may be suitably anchored and sealed either to the cable head and other terminal facilities or to the adjacent portions of the cable body. In either case a potting compound may be employed to seal about the ends of jacket 18 and conductors 16 following which a protective tape wrapping is preferably added for additional protection.

Although the technique of expanding and salvaging existing trunk line assemblies of the wire harness and cable types have been emphasized hereinabove, it will be understood that the technique is equally applicable to conductors enclosed within other types of protective sheathing as, for example, flexible armor and rigid conduits. Accordingly, the term sheathing as used herein will be understood as including sheathing structures of the many types known .to this art. It is further pointed out that the seamed jacketing employed to enclose the new conductors along with the existing trunk assembly includes jacketing of a wide variety of materials in addition to the preferred heat reactive plastic material.

While the particular harness assembly and method of making same herein shown and disclosed in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or de sign herein shown other than as defined in the appended claims.

I claim:

1. In combination with a cable harness assembly of the type having a main trunk comprising a plurality of parallel conductors compactly bundled together and enclosed between their terminal ends by a protective sheath; that improvement which includes one or more electrically insulated conductors extending along the exterior of said sheathed main trunk, and longitudinally seamed tubular jacket means enclosing both said sheathed main trunk and said conductor extending along the exterior thereof characterized in that said jacket means has a main body strip formed of heat reactive plastic material which shrinks substantially upon being heated thereby permitting said jacket means to be assembled loosely about said sheathed main trunk and conductors and then heat shrunk snugly thereto by heating the jacket means.

2. The combination defined in claim 1 characterized in that said jacket means comprises a main body strip of flexible sheet plastic material having along its opposite edge portions interlocking tongue-and-groove seam-forming means engageable to hold said jacket means assembled about said sheathed main trunk and external conductors.

3. That improvement for prolonging the service life of cable harness assemblies when an existing harness assembly becomes inadequate for any reason which improvement comprises, extending additional conductors along the exterior of the existing inadequate harness assembly and then enclosing the main trunk portion of said harness assembly and the additional conductors lying thereagainst within a tubular slightly oversize jacket of fluid-tight impervious flexible sheet material having a longitudinal seam therealong effective when closed to hold said jacket in assembled position about the contents thereof, said jacket being formed of heat reactive plastic having a pronounced shrinkage capability upon being heated, and shrinking said longitudinally seamed jacket to said harness by applying heat thereto.

4. That improvement defined in claim 3 characterized in that said additional conductors are wrapped spirally about said inadequate harness assembly to aid in holding said conductors assembled compactly and in a distributed manner against the exterior of said trunk before said jacket is closed thereabout.

5. That method of increasing the circuit handling capabilities of an existing sheathed cable assembly which comprises, extending a plurality of additional conductors along the exterior of said cable assembly and thereafter enclosing the main trunk portion of said assembly in a tubular jacket of flexible impervious heat reactive plastic stripping having lateral edge portions shaped to interfit and to form a fluid-tight closure seam holding said jacket assemoled loosely about said cable assembly and additional conductors, the opposite ends of the additional con-ductors being adapted for connection to equipment in a manner providing additional circuits in cooperation with the conductors of the existing sheathing cable, said heat reactive plastic stripping having the property of taking a permanent shrunk set upon being heated, and heating said jacket-enclosed cable assembly to shrink said jacket snugly about the contents thereof.

2,027,962 Currie Jan. 14, 1936 6 Rugeley et al Nov. 18, 1941 Hanson Oct. 20, 1942 OTHER REFERENCES pages).

(Copy received in Division 69, March 7, 1958.) 

1. IN COMBINATION WITH A CABLE HARNESS ASSEMBLY OF THE TYPE HAVING A MAIN TRUNK COMPRISING A PLURALITY OF PARALLEL CONDUCTORS COMPACTLY BUNDLED TOGETHER AND ENCLOSED BETWEEN THEIR TERMINAL ENDS BY A PROTECTIVE SHEATH; THAT IMPROVEMENT WHICH INCLUDES ONE OR MORE ELECTRICALLY INSULATED CONDUCTORS EXTENDING ALONG THE EXTERIOR OF SAID SHEATHED MAIN TRUNK, AND LONGITUDINALLY SEAMED TUBULAR JACKET MEANS ENCLOSING BOTH SAID SHEATHED MAIN TRUNK AND SAID CONDUCTOR EXTENDING ALONG THE EXTERIOR THEREOF CHARACTERIZED IN THAT SAID JACKET MEANS HAS A MAIN BODY STRIP FORMED OF HEAT REACTIVE PLASTIC MATERIAL WHICH SHRINKS 